This invention relates to improved semiconductor device packages and, more particularly, to a low-cost semiconductor device package structure having quick-connect terminals, an integral heat spreader, an insulating plastic body, and the ability to utilize existing prepackaged semiconductor devices of known characteristics to achieve overall low cost, ease of use, and high reliability.
Quick-connect terminals are a convenient means for making electrical connection to a variety of electrical components where substantial power handling capability is required. Many electrical components are available with these types of terminals and are widely used in industry. However, it is only recently that semiconductor devices have been built with quick-connect terminals because of the difficulties encountered in attaching the relatively heavy terminals to the fragile semiconductor chip in such a way that the forces exerted on the terminals during normal use are absorbed by the device package and not transmitted to the semiconductor chip or fragile interconnections.
As used herein, quick-connect terminals refer to those electrical terminals which can be readily contacted by mechanical means, preferably by plugs, wire wrapping, or spring clips, as opposed to welding, soldering or other metallurgical bonds.
Several semiconductor power device packages with quick-connect terminals have been recently introduced. However, these prior art designs have shown poor power cycling reliability. They use many separate parts, are poorly suited for mechanized assembly, and they are expensive to manufacture. Thus, a need continues to exist for a semiconductor device pckage having quick-connect terminals which is reliable, of low cost, readily adaptable to automated or semi-automated assembly, and easy to electrically isolate from the surfaces on which it is to be mounted.
A significant factor which delays the widespread commercial adoption of a new package configuration is the concern exhibited by many users about the reliability of semiconductor devices when encapsulated in a new and untried package. It is well known that there is significant interaction between the semicondcutor chip and the materials and methods used to encapsulate it and that frequently these interactions can have deleterious effects upon the reliability of the semiconductor device. Ordinarily, substantial amounts of life test data and field experience are demanded by prospective users before a new chip-package combination can achieve widespread acceptance. Each time the geometric forms and material selections are changed, particularly for those items in direct contact with the semiconductor chip (e.g. die coating materials placed over the chip, heat spreader geometry, lead bond positions and attachment techniques, etc.), a cycle of slow customer acceptance is repeated. Thus, a quick-connect terminal package configuration which can utilize prepackaged devices of known behavior and reliability, and with a long manufacturing history, has substantial advantages in achieving rapid customer acceptance since the crucial relationships between the semiconductor chip and its immediate package environment can be preserved. The manufacturing history and reliability of the prepackaged device is directly transferrable to the new package configuration and more rapid customer acceptance can be expected. There is a considerable cost saving to both manufacturer and user as a consequence of the reliability testing and product qualification programs that can be reduced or simplified.
Accordingly, an object of the present invention is to provide a quick-connect package configuration of lower cost.
An additional object of this invention is to provide a quick-connect package configuration of improved reliability.
A further object of this invention is to provide a quick-connect package configuration making use of fully tested prepackaged devices of established manufacturing history, low manufacturing costs and known reliability.
A further object of this invention is to provide a quick-connect package configuration which does not require use of an internal isolator to conveniently make possible electrical isolation of the semiconductor device from the mount to which the package is attached, and which can be easily insulated from a mounting surface without elaborate bushings or sleeves.
An additional object of this invention is to reduce the number of piece parts which must be assembled.
A further object of this invention is to provide a configuration suitable for automated assembly in order to further reduce the cost.
An additional object of this invention is to provide an insulated body and attachment means which is electrically insulated from the semiconductor device, its leads, and its heat spreader.
It is a further object of this invention to provide a quick-connect package configuration which can conform to industry standard terminal and base outline geometries.